Dowels of various types are known in the art. Such devices are typically used in the furniture industry for joining the various components of a furniture assembly. Dowels are used in other industries as well, for example, dowels may be used to join landscaping timber. During construction, a dowel is driven into an opening, such as a circular shaped bore, of one of the furniture components that comprise the assembly. The second furniture component to be connected to the first furniture component is also provided with an opening for the dowel. The opening in the second furniture component is aligned with the opening in the first furniture component. The dowel that is mounted to the first component is then inserted and driven into the opening in the second component. Pressure may be applied to the two components when the dowel is being driven into the opening in the second component. Since the dowel's diameter is greater in size then the diameters of the openings, the dowel is held in the openings by the frictional forces exerted on the dowel's outer side walls by the inner side walls of the openings in the two components.
However, existing dowels known in the art have some inherent disadvantages. One of the disadvantages with existing dowels is that, when inserting the dowel in the openings of the adjoining components, a high pressure must be applied to overcome the frictional force which acts on the contact surface between the outer wall surface of the dowel and the inner wall surface of the opening and acts opposite to the dowel's insertion direction. As a result, when the dowel is inserted into the openings, an undesirable deformation of the opening's inner wall surface may occur. This deformation may impair the connection of the dowel with the component. Further, if the dowel experiences extreme stress the dowel may be damaged and may break. Safety issues are also a concern, if the stresses on the dowel are such that the dowel splits into more than one piece, the user may be injured by material splinters.
The present invention overcomes these and other problems inherent in existing dowels. The present invention provides a dowel that has multiple sections that decrease in diameter over the longitudinal axial length of the dowel. The decreasing diameters of the dowel sections minimize the frictional forces and resultant stresses exerted on the dowel during insertion of the dowel into the component openings. Thus, the user experiences easier insertion of the dowel into the openings of the components. Also, the dowel is less prone to breakage and user safety is enhanced. Further, while the dowel provides a secure, locked component fit, the components experience considerably less deformation when the dowel is inserted into the respective openings. Since component deformation is minimized, the components last longer and their appearance does not deteriorate.
The dowel of the present invention requires component openings that can accept the dowel. The prior art also does not provide a tool or device that can create these specifically shaped openings. Thus, a drill bit that can create these openings is needed in the art. The present invention provides a drill bit that has multiple sections that decrease in diameter over the longitudinal axial length of the drill bit. The drill bit may be used to form component openings that are properly shaped and sized to accept the dowel of the present invention.